Hey! I was trying to control Sonar from 2 identical systems with the same MIDI driver and 2 seperate interfaces. So I had 2 Gen surfaces each assigned to different interfaces. This didn't separate the input path. So I have tried installing 4 different interfaces each with its own driver. This still didn't work. Is this possible? It works fine when Sonar is the master but as a slave it won't separate the input device.

I guess I am not alone with hard time to understand what you are really asking. You have better chance to get a good advise in case you specify which controllers you have and which MIDI interfaces you try to use.
 
Also have you understood my comment in your other thread? Before you can use something as a Control Surface, it should work as a normal MIDI input.
 
Please do not get me wrong, there are many people which want and probably will be able to help you. But more information is needed from your side.

I just found this reply.  It turns out that the Generic Midi Surface must be Omni and will not discriminate between the MIDI inputs that are active on the DAW.  So if you have more than 1 port active,  the MIDI surface would be able to read from both sources. Not the greatest,  but it's an old program.  I was wanting to set up to separated MIDI surfaces that were identical except for the port that was receiving the data.